This application claims the benefit of Japanese Application No. 2000-005323, filed in Japan on Jan. 14, 2000, which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a pulse-width-modulated (PWM) control apparatus, a motor driving apparatus, a stage apparatus, an exposure apparatus, a device that is manufactured by means of this exposure apparatus, and a device manufacturing method.
2. Description of the Background Art
A semiconductor exposure apparatus is constructed from a reticle stage that carries a reticle (or mask), a wafer stage that carries a wafer, and a projection optical system that projects a pattern formed on the reticle onto the wafer and exposes this pattern. The respective stages are appropriately driven by motors and motor driving apparatuses that drive these motors, so that the pattern formed on the reticle is accurately projected and exposed in a specified position on the wafer. Linear motors are used as the motors that drive the respective stages, and high-efficiency pulse-width-modulated (PWM) amplifier circuits are used as the circuits that drive these linear motors. Since it is necessary that the stage of the projection exposure apparatus be driven with a high degree of precision, performance that offers high precision and a high S/N ratio is required in this PWM amplifier circuit. Accordingly, a switching regulator, etc., which allows sufficient regulation is used in the power supply.
However, large-capacity switching regulators are expensive, and have a large volume and weight, so that a large proportion of the volume and weight of the semiconductor exposure apparatus is occupied by such a switching regulator. On the other hand, in cases where a simple transformer-less power supply is used, high-frequency components of the power supply frequency remain in the output of the amplifier circuit, so that there is a problem in that performance that offers high precision and a high S/N ratio cannot be guaranteed.
The present invention provides a PWM control apparatus which makes it possible to to realize a motor driving apparatus that has high precision, a high S/N ratio, low cost, a small volume and a low weight.
A motor driving apparatus of the present invention includes a PWM control apparatus, a stage apparatus that uses this motor driving apparatus, an exposure apparatus that uses this stage apparatus, a device that is manufactured by means of this exposure apparatus, and a device manufacturing method.
A PWM control apparatus of the present invention includes a triangular wave generating circuit for generating a triangular wave, a comparator for comparing an input signal and the triangular wave and outputting a PWM signal with a pulse width corresponding to a voltage level of the input signal switching elements connected to a power supply, and for switching a voltage from this power supply on and off and output a voltage based upon the PWM signal, and an adjustment circuit for adjusting a duty ratio of the PWM signal according to fluctuations in the voltage of the power supply.
The adjustment circuit of the present invention divides the voltage of the input signal by the voltage of the power supply.
The adjustment circuit includes a circuit that adjusts the amplitude of the triangular wave according to fluctuations in the voltage of the power supply .
The adjustment circuit multiplies a triangular wave output from the triangular wave generating circuit by the voltage of the power supply.
The adjustment circuit adjusts a voltage level of a triangular wave generating circuit power supply that supplies power to the triangular wave generating circuit in proportion to fluctuations of the voltage of the power supply.
The triangular wave generating circuit of the present invention includes switching circuits that alternately switch between two different signal levels at specified frequencies, and integrating circuits that integrate outputs of the switching circuits and output a triangular wave, and the adjustment circuit includes an amplifier circuit that outputs the two different signal levels where a signal level difference of the two signal levels varies in proportion to fluctuations of the voltage of the power supply .
A PWM control apparatus of the present invention includes a triangular wave generating circuit for generating a triangular wave, a comparator for comparing an input signal and the triangular wave and outputting a PWM signal with a pulse width corresponding to a voltage level of the input signal, switching elements connected to a power supply for switching a voltage from power supply on and off and outputting a voltage based upon the PWM signal, and an adjustment circuit for adjusting the voltage level of the input signal that is input into the comparator according to a variation of the voltage of the power supply.
A PWM control apparatus of the present invention includes a triangular wave generating circuit for generating a triangular wave, a comparator for comparing an input signal and the triangular wave and outputting a PWM signal with a pulse width corresponding to a voltage level of the input signal, switching elements connected to a power supply for switching a voltage from the power supply on and off and outputting a voltage based upon the PWM signal, and an adjustment circuit for adjusting an amplitude of the triangular wave according to a variation of the voltage of the power supply.
A motor driving apparatus of the present invention comprises a current amplifier circuit which includes a PWM control apparatus of the present invention.
A stage apparatus of the present invention comprises a stage that carries an object of movement, a motor that drives the stage to move the object of movement, and a motor driving apparatus of the present invention which drives the motor.
An exposure apparatus of the present invention forms a specified pattern on a substrate by means of exposure, and is equipped with at least a stage apparatus of the present invention which carries and moves either a mask or a substrate.
A device of the present invention which is manufactured by means of an exposure apparatus of the present invention.
A device of the present invention which is manufactured by using an exposure apparatus of the present invention and comprises a process in which the exposure is performed by means of the exposure apparatus of the present invention.
A PWM control method of the present invention in which the voltage from a power supply is switched on and off and output on the basis of a PWM signal having a pulse width that corresponds to a voltage level of an input signal, and is devised so that a duty ratio (degree of modulation) of the PWM signal is adjusted based upon fluctuations in a voltage level of the power supply.